whenString<T> function

T? whenString<T>(
  1. String value,
  2. Map<String, ValueGetter<T>> conditionMap
)

English: Used to replace the switch method, because in some scenarios, an error warning of Case expressions must be constant;
If there is value in Map.keys of conditionMap, execute its corresponding ValueGetter method

中文: 用于取代switch方法，因为有些场景使用switch会出现Case expressions must be constant.的错误警告；
如果conditionMap的Map.keys中有value的话，执行其对应的ValueGetter方法

example:

int? index = whenString<int>("banana🍌", {
  "water" + "melon": () {
    return 1;
  },
  "apple": () {
    return 2;
  },
  "orange": () {
    return 3 ;
  },
  "banana" + "🍌": () {
    return 4;
  },
  "grape": () {
    return 5;
  },
});

Implementation

T? whenString<T>(String value, Map<String, ValueGetter<T>> conditionMap) {
  return conditionMap[value]?.call();
}